The influence of the Asian summer monsoon on volcanic aerosol transport in the UTLS region

This study analyses the influence of the Asian summer monsoon on volcanic aerosol transport. Realistic, altitude-resolved SO 2 emissions of a middle-latitude volcanic eruption (Sarychev 2009) and a tropical volcanic eruption (Nabro 2011) were retrieved and used to initialize the simulations of the long-range transport and dispersion of the sulfate aerosol plumes. The barrier effect of the Asian summer monsoon anticyclone (ASMA) isolated the Sarychev eruption plume outside of the ASMA but constrained the Nabro eruption plume inside of the ASMA, which is most evident in the UTLS region between isotropic surfaces of 360–420 K. Meanwhile, the ASMA could transport a fraction of the plume outside of ASMA quasi-horizontally to the tropical tropopause layer along the southeastern periphery of the anticyclonic circulation, and lift the volcanic plume inside the ASMA anticyclonically across the tropopause with an ascent rate of approximately 0.8 K/day. By enhancing the meridional transport in the UTLS region and lifting volcanic aerosols across the tropopause, the ASMA significantly expanded the potential effects of volcanic eruptions.